http://www.freedesktop.org/wiki/Software/systemd/TipsAndTricks/
http://www.freedesktop.org/wiki/Software/systemd/FrequentlyAskedQuestions/

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/chap-Managing_Services_with_systemd.html

Systemd CentOS 7 service cheatsheat
http://habrahabr.ru/company/infobox/blog/241237/

Writing custom .service and .target
https://habrahabr.ru/post/275645/

man
http://www.freedesktop.org/software/systemd/man/systemd.unit.html

systemd
systemd.directives
  systemd.unit
    Specifiers (%h, $H, ...)
  systemd.service
    http://serverfault.com/questions/413397/how-to-set-environment-variable-in-systemd-service  
  systemd.exec
    exec config
  systemd.socket
systemd-system.conf

???
systemd.special

.service
.device
  sys-subsystem-net-devices-enp2s0.device
.mount
.timer
.swap


Units:
https://wiki.archlinux.org/index.php/Systemd#Using_units

man systemd.unit
systemctl list-units [--all]
    status|enable|disable|start|stop|restart|... <unit>

    enable  - add a service to appropriate target via symlink
    isolate - ???
    status
        -l -n 50

    list-unit-files
        -t service --state=enabled --no-legend --no-pager "prefix*" |awk '{ print $1 }'

Dependencies:
Removed symlink /etc/systemd/system/multi-user.target.wants/qbittorrent.service

sudo systemctl [rescue|default|emergency]

Configuration:
systemd-system.conf
/etc/systemd/sytem.conf


??? /etc/systemd/system/display-manager.service


inotify:
http://www.cyberciti.biz/faq/making-changes-to-proc-filesystem-permanently/

/etc/sysctl.conf
/etc/sysctl.d/99-sysctl.conf:
# Increase inotify max watchs per user
fs.inotify.max_user_watches = 100000

cat /proc/sys/fs/inotify/max_user_watches


User-based services:

https://wiki.archlinux.org/index.php/Systemd/User
http://superuser.com/questions/476379/how-do-i-setup-a-systemd-service-to-be-started-by-a-non-root-user-as-a-user-daem

sudo ls -la /usr/lib/systemd/user
sudo vim /usr/lib/systemd/system/qbittorrent.service

systemctl enable btsync@svetah.service
or just
systemctl enable btsync@svetah

User DBus:
https://bbs.archlinux.org/viewtopic.php?pid=1348186#p1348186

config path:

--system mode
/usr/lib/systemd/system/
  units provided by installed packages
/etc/systemd/system/
  units installed by the system administrator

--user mode


timedate:
timedatectl [status|list-timezones]

systemd-timedated.service
systemd-timesyncd.service

other:
systemd-firstboot.service

machinectl
systemd-machine-id
systemd-machined.service


cgroups:
systemd-cgls
systemd-cgtop